1. Field of the Invention:
The present invention relates generally to a method and apparatus for cooling a rod of a coil form, immediately after the hot-rolling thereof, and more particularly to improvements in the arrangements of the nozzle portions provided within the bodies of the cooling floors themselves, which nozzle portions project cooling fluid against the rod of the coil form during it transportation upon a chain conveyor, a series of loops of the aforenoted rod being laid flat upon the chain conveyor and spaced at a given pitch from one another.
2. Description of the Prior Art:
It has been a common practice when cooling a rod of a coil form, that immediately after the hot-rolling thereof, the hot-rolled rod is wound into a coil form by means of a laying cone, and subsequently, a series of loops of the rod is sequentially placed upon a conveyor, and more particularly upon the rails thereof whereby the wire loops are able to be transported by means of endless chains along the cooling bed with the series of loops of the rod being laid flat upon the rails and spaced at a given pitch from one another, during which time cooling fluid is projected upwardly through means of nozzles provided within the cooling floors so as to thereby cool the rod for heat treatment thereof.
Another attempt is disclosed within Japanese Patent Publication No. Sho 42-15463, within which an increased quantity of air is projected against the lateral high density portions of the rod loops, while the quantity of cooling air being projected against the central portion of the rod is simultaneously decreased, as viewed in the transverse direction, for the pupose of achieving uniform cooling of the rod.
Still other attempts have been disclosed within Japanese Patent Application No. Sho 49-15608 and Japanese Patent Application No. Sho49-15609, within which a large quantity of air is projected against the lateral high density portions of the rod, while the rod of the coil form is oscillated vertically or conveyed in a zig-zag pattern upon a coding bed so as to similarly achieve uniform cooling of the rod. However, these prior art attempts nevertheless pose problems which remain unsolved.
More particularly, as seen within FIGS. 1 and 2, it has been a general practice that the hot-rolled rod is transferred from a laying cone 1 onto a cooling bed 3 in the form of a coil 4 whose loops are laid flat thereon and spaced at a given pitch from one another. The rod is disposed upon rails 5 provided upon the cooling bed 3 and transported thereon by means of endless conveyor chains 6 which are disposed parallel to the rails 5. During the transportation of the rod, the rod is cooled with air streams being projected through nozzles 7 provided within the cooling bed 3. However, as the rod 4 of the coil form is placed upon the rails 5 and transported by means of the chains 6, by being hooked by means of fingers of the chains 6, the result is that the portions of the rod which contact the rails 5 and chains 6 will not be sufficiently cooled with cooling fluid because the cooling fluid being projected through means of the nozzles 7 is directed parallel with the rails 5 and chains 6. This leads to an increase in the extent of variation in the cooling rate of the rod over the entire length thereof, and hence an increased extent in the variation in the mechanical strength thereof.
Another difficulty in cooling a rod of a coil form is that the lateral circumferential portions of the loops of the rod provide high density portions, as viewed in the vertical direction, whereby the cooling fluid cannot readily penetrate such high density areas, as compared with the central portion of the loops of the rod which are spaced a further distance from each other than the loops of the aforenoted high density portions of the rod.This then leads to the failure to provide uniform cooling for the rod, and hence uniform mechanical properties thereof.
As has been described earlier, to cope with these problems, there have been proposed many attempts such as disclosed within Japanese Patent Application No. Sho 49-15608 and Japanese Patent Application No. Sho 49-15609, within which a rod of a coil form is oscillated in the vertical direction, or alternatively, a rod is transported, following a zig-zag pattern, in an attempt to achieve uniform cooling. However, this brings about other shortcomings, that is, the possiblity of causing variation in the pitch of the loops, an irregular shape of the loops, and cracking within the skin of the rod due to such oscillations or vibrations. In addition, the construction of the apparatus becomes quite complex, thereby also presenting the possiblity of not using the same in practical applications.